Head-rest.



no. 642,404. Patented Ian. 30, 1900. B. M.'WILKERSON.

HEAD REST.

(Application filed Apr. 29, 1899.) (No Model.) 2 Sheats-$heet I.

t i I WITNESSES; INVENTOR:

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Patented Jan. 30, I900.

B. WILKERSON.

HEAD REST.

(Application filed Apr. 29, 1899.

2 Sheets-Sheet 2.

(No Model.)

WITNESSES: INVE'NTOR:

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BASIL M. WILKERSON, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE S. S. WVHITE' DENTAL MANUFACTURING COMPANY, OF PHILADELPHIA, PENN SYLVANIA.

HEAD-REST.

SPECIFICATION forming part of Letters Patent No. 642,404, dated January 30, 1906.

Original application filed Novem r 25, 1898, Serial No. 697,344. Divided and this application filed April 29, 1899. Serial llo. 714,962. (No model.)

To aZZ whom it may concern.-

Be it known that I, BASIL M. WILKERSON, a citizen of the United States,residing in the city of Baltimore,in the State of Maryland,have invented certain new and useful Improvements in Head-Rests; and I do herebydeclare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to IO make and use the same.

My invention relates to head-rests for dental chairs; and it consists of certain improvements in the head-rest proper and also in the support or carrier therefor. The said support or carrier is in some respects similar to the head-rest support or carrier shown, described, and claimed in United States Letters Patent No. 581,670, granted to one April 27, 1897.

The object of my present invention is to improve the head-rest support or carrier of said patent and at the same time provide an improved head-rest proper.

The present application is a division of my pending application, Serial No. 697,344, filed November 25,1898. 7

In the accompanying drawings, which illustrate a suitable embodiment of my improvements, Figure 1 is a view in side elevation of the entire head-rest, including the head-rest 3o proper and its support orcarrier. Fig. 2 is a View in rear elevation of the same, with the head-rest pads omitted. Fig. 3 is a top or plan view of the head-rest proper. Fig. 4 is a View in front elevation of the lower section of the head-rest support or carrier. Fig. 5 is a central vertical sectional view of the headrest support or carrier. Fig. 6 is a front or face view of the toggle-lever of the head-rest support or carrier detached.

As in mybefore-rnentioned patent,the headrest support or carrier consists of a jointed stem composed of three sections S, S, and S united together by universal joints. The

lower section S, which is tubular or hollow, is mounted and adapted to slide up and down on a dovetailed way P of the back of a dental chair, a portion only of this dovetailed, way being shown in Fig. 5, the section S being formed with a base portion grooved to fit upon and embrace the dovetailed way. To the upper section S is attached the supporting-bar T of the head-rest proper, which will be more particularly referred to hereinafter. The intermediate section S is connected to its two fellow sections by ball-and-socket joints. The upper section S has a ball 8 on its lower end, which fits in a socket on the upper end of the intermediate section S, this socket being formed by a sleeve 3, screwed upon the section S, and by the concave head 8 of an endwise-movable presser-rod S fitted in the tubularintermediate section S. The lower end of this section Shas a ball 8 on its lower end, which fits in a socket on the upper end of the lower section S. This socket is formed by a sleeve 8 screwed upon the section S, and the concaved head 5 of an endwise-movable pushpiece S fitted in the upper tubular or recessed end of the section S. The presser-rod S passes through and slightly beyond the ball 8 on the intermediate section S and bears upon the concave surface of the head 8 of the pushpiece S Suitable mechanism is provided for clamp ing the head-rest carrier upon the dovetailed way P and simultaneously clamping the balljoints of the head-rest carrier together, whereby the head-rest carrier may be made rigid and the same locked to the back-pad carrier. This mechanism is shown as consisting of a toggle-lever S which acts to cause the pushpiece S to clamp theball s in its socket, the same movement being transmitted to the presser-rod S to clamp the ball 8 in its socket, the toggle-lever at the same time clamping the lower section S of the head-rest carrier to the dovetailed way P of the chairback. The toggle-lever S is placed in the section S in the position shown in Figs. 4 and 5,with its opposite ends bearing at the top against the push-piece S and at the bottom against an abutment s on the interior of thissection. The end of the toggle-lever which bears against the abutment s is beveled, so that whenthe toggle-leveris straightened this beveled or wedge-shaped end will be forced against the dovetailed way P A pressurescrew S provided with an external operating handle or knob 8 enters the section S through a suitable screw-threaded socket in aposition where its inner end will bear against the toggle-lever. By screwing in the pressure-screw it will straighten the lever, with the effect of forcing up the push-piece S, and thus looking both joints of the headrest carrier and the carrier to the chair-back.

It is desirable when the pressure-screw S is operated to unclamp the joints of the headrest carrier for the purpose of adjusting the head-rest that the various joints of the carrier be self-sustainingthat is to say, be yieldingly supported and yet not allowed to drop or move except when direct pressure is applied to the head rest or carrier. This selfsustaining adjustment or condition is required at all times for the universal or balland-socket joints of the carrier when the same is unlocked; but the joint between the vertically-adjustable carrier and the chair-back should be perfectly free when it is desired to adjust the carrier up or down, yet this look should be selfadjusting when the universal joints are being adjusted. These important results are accomplished in the following manner: Fitted upon the lower end of the stem of the push-piece S is a socketed slidepiece 5*, adapted to slide upon the stem of said push-piece inside of a recess formed in the upper end of the lower section S of the head-rest carrier. One end of the toggle-lever bears against the slide-piece for pushing the push-piece upwardly, and a spring .9 surrounding the stem of the push-piece, is confined between the head of said push-piece and the upper end of the slide-piece S and acts with a tendency to force the push-piece and the slide-piece apart. A shoulder S on the slide-piece S adapted to abut against a shoulder s on the section S, limits the downward movement of said slide-piece. A spring S preferably having a coil in it, is secured atits opposite ends to the respective members of the toggle-lever for the purpose of holding said members together without interfering with their free movement, yet at the same time insuring the bending or flexing of the toggle-lever when the same is not in action. The lower member of the toggle-lever S has an opening 3 through it near its lower end, and a headed pin or bolt 8, projecting from the section S, enters said opening. Aspring s surrounds the pin 8 and is confined between the head of said pin and a shoulder s on the toggle-lever. Theobject of this spring is to insure the toggle-lever being released from frictional engagement with the dovetailed way of the back-pad carrier when the pressure-screw is operated sutliciently to allow of this movement.

From the above description it will be understood that by screwing the pressure-screw in tightly the toggle-lever is caused to firmly lock the carrier to the back-pad carrier against vertical movement and to simultaneously firmly lock both universal joints of the carrier and that by unscrewing the pressure-screw to a certain extent all of the joints of the carrier are in a self-sustaining conditionthat is to say, the spring 5 is permitted to exert sufiicient pressure on all the joints to render them tight enough to maintain the carrier in any position to which it may be moved, but leaving it in a condition to be adjusted by pressure applied to the head-rest or its carrier. By unscrewing the pressure'screw still farther the spring 5 forces the slide-piece S downwardly until its shoulder s abuts against the shoulder s of the carrier-section S,when the spring 3 cannot act upon the toggle-lever. When in this condition, the universal joints are still self-sustaining, as before; but the joint between the carrier and the chair-back is relieved of all friction, and the carrier may be freely moved up and down without disturbing the adjustment of the universal joints.

The head-rest proper consists of two pads T T, which are connected to the supportingbar T by means of compound or S-shaped clamp-links T T (See particularly Figs. 1 and 3.) These links are each provided with eyes or openings in their opposite ends,which fit upon studs or pivots i on the outer opposite ends of the supporting-bar and studs or pivots t on the head-rest pads. In order to clamp the head-rest pads in their adjusted position, each link is provided with a clampscrew T having an operating handle or knob T and which passes through an opening in one end of the link and through an opening in the body of the link and screws into the opposite end of the link. Screws t screwing in the links and entering slots i in the studs 15, serve to prevent the links from accidentally coming off the studs and at the same time limit the turning movement of said links about said studs. The pads may be kept in place on the links by means of a pin or spring in each link engaging an annular groove in each stud t of the pads. This construction enables the links to turn about their pivotal connection with the supporting-bar in a line with the plane of said bar or toward and away from each other and the head-rest pads to turn about their pivotal connection with the links, wherebya very wide range of adjustment of the headrest is permitted. Another advantage of this construction is that the pads are readily detachable from their clamp-links and may be reversed.

It will of course be understood that the details of construction herein shown and described may be varied without departing from the spirit or scope of my invention and that the particular head-rest proper may be used in connection with any suitable support or carrier and that the particular support or carrier may likewise be used in connection with any suitable form of head-rest proper.

I claim as my invention- 1. The combination of a head-rest-supportin g stem or carrier composed of sections, uni- Versal'joints between the sections of said stem, a handle located upon one of the sections,

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iiie'ans controlled by said handle for looking all of said joints simultaneously and by one movement of the handle, and means for yieldingly supporting the stem when the joints have been unlocked by the handle, substantially as and for the purpose described.

2. In combination with a chair-back, a headrest-supporting stem or carrier composed of sections, universal joints between the sections of said stem, a vertically sliding connection between the lower section of said stem and said chair-back, means for simultaneously locking said universal joints and said Vertically-slidin g connection, and means for yieldingly clamping said joints and said connection, when said locking means are unlocked, substantially as and for the purpose described.

3. In combination with achair-back, a headrest-supporting stem composed of sections, universal joints between the sections of said stem, a vertically-sliding connection between the lower sect-ion of said stem and a chair- -back, a handle located upon said lower seo-' tion, means under the control of said handle for simultaneously locking said universal joints and said vertically-sliding connection, means for yieldingly clamping said universal joints when said locking means are unlocked,

lower section for rigidly clamping the same ball and socketjoint, and a spring acting with a tendency to force said push-piece and said slide-piece awayfrom each other, substan tially as and for the purpose described.

5. The combination in a head-rest, of an adjustable supporting stem or carrier, a supporting-bar adj ustably connected midway its length to said supporting stem or carrier, studs projecting at right angles from the opposite ends of said supporting-bar, two clamplinks each of which is fitted at one end to swivel about the respective studs of the supporting-bar, whereby said links are capable of being rocked in a line with the plane of said supporting-bar or toward and away from each other, two head-rest pads each pivoted to the outer end of the respective clamp-links, whereby said pads are capable of being rocked in the line of movement of said clamp-links, and means for simultaneously clamping and unclamping the pivotal connections of each clamp-link and its respective head-rest pad and stud of the supporting-bar, the clamping means for one link being independent of the clamping means for the other link, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

, BASIL M. WILKERSON.

Witnesses:

FRANK W. WAGNER, S. O. MALONE. 

